File in Section:

Service Bulletin

Bulletin No.:

16-NA-175

Date:

June, 2016

TECHNICAL
Subject:

Shake and/or Shudder During Light Throttle Acceleration Between 48 and 104 KM/H (30
and 65 MPH) at a Steady State

Brand:

Model:

Cadillac
Chevrolet

Model Year:
from

to

Escalade
Models

2016

2016

Silverado

2016

2016

GMC

Sierra

2016

2016

GMC

Yukon
Models

2016

2016

VIN Breakpoint

Engine:

Transmission:

All vehicles Built after
November O1, 2015

Equipped with
5.3L or 6.2L
Engine (RPOs
L83, L86)

Equipped with
8L90 Automatic
Transmission
(RPO M5U)

Involved Region or Country

North America

Condition

Some customers may comment on any of the following conditions:
• A shake and/or shudder during light throttle acceleration between 48 and 104 km/h
(30 and 65 mph) steady state driving when transmission is not actively shifting gears.
• A shudder feeling that may be described as driving over rumble strips or rough
pavement.
• Shudder feeling is evident in both Drive and M7 mode.

Diagnosis Instructions
To ensure TCC shudder is diagnosed correctly, please
drive the following schedule on a smooth road with
transmission sump temperature between 50°C (122°F)
- 70°C (158°F).
Important: For some road conditions, it may be
required to apply the brake pedal and throttle
simultaneously to stay within desired engine torque
range.
Press and hold the tow-haul mode button for 5 seconds
to disable grade braking to prevent downshifts
during test.
Run the following tests for 3 operational modes:
A. Normal Operation (GDS2 for viewing only).
B. GDS2 Commanding TCC in Disabled Operation.
(TCC Open).
C. GDS2 Commanding TCC in Enabled Operation.
(TCC Locked).
TEST:

Drive the vehicle in 8th gear, VS mode, with a
transmission input speed of 1,050-1,300 rpm with
(approximately 64-89 km/h (40-55 mph)) constant
throttle input, and engine torque 200-375 N•m

Copyright 2016 General Motors LLC. All Rights Reserved.

To confirm TCC shudder, the vibration concern must be
created in normal operation (Mode A) of the test. If the
concern is gone with the torque converter clutch
disabled (Mode B, TCC Open) and is gone when the
torque converter clutch enabled (Mode C, TCC
Locked), the vibration root cause is TCC shudder
and the fluid flush procedure corrective action
described below should be performed.
If the concern is not present in Mode A, then the
vibration concern is not TCC shudder. If the concern is
still present with the torque converter clutch disabled
(Mode B) or with the torque converter clutch enabled
(Mode C, TCC slip speed at zero), the root cause of
vibration is NOT shudder. Vibrations not identified as
shudder should be further investigated using the
"Vehicle Vibration Diagnosis and TAC Requests for
Assistance with Vibration Related Complaints" Bulletin.

Service Procedure
Important: Requires NEW DEXRON HP Fluid (GM
Part No. 19331925, in Canada 19331926).
Step 1: Cooler Flush, Drain, Clean pan/magnet,
Replace Filter (If needed), Oil Fill, & Circulate New
Fluid
1 a.) Flush the cooler lines and cooler using published
SI Procedures.

Page 2

June,2016

1 b.) Remove the transmission fluid pan and drain
transmission fluid following SI procedures for the
application you're working on. Discard all oil.
Note: If you find that the fluid is cloudy, milky, or
appears to be contaminated with water or engine
coolant, DO NOT proceed with below steps. Follow
Both SI Procedures for "Cooling System Leak Testing
(L83, L86)" and "Engine Coolant/Water in
Transmission."
1 c.) Clean the pan/magnet if any metallic particles
present and replace transmission filter if debris is
found.
1 d.) Install the transmission fluid pan and refill with
new transmission fluid using enough volume to have oil
come out of oil level check plug.
Important: Operate the vehicle on the hoist for 10
minutes. Cycle through all forward gear ranges,
Reverse and Neutral.
Step 2: Drain, Oil Fill, & Circulate New Fluid
2 a.) Remove the transmission fluid pan and drain
transmission fluid again. Discard all oil.
2 b.) Install the transmission fluid pan and refill with
new transmission fluid using enough volume to have oil
come out of oil level check plug.
Important: Operate the vehicle on the hoist for 10
minutes. Cycle through all forward gear ranges,
Reverse and Neutral.

Bulletin No.: 16-NA-175

Step 3: Drain, Oil level Set, and Drive to Evaluate
3 a.) Remove the transmission fluid pan and drain
transmission fluid again. Discard all oil.
3 b.) Install the transmission fluid pan and refill with
new transmission fluid following the "Fluid Fill
Procedure" in SI to obtain correct fluid level.
The shudder should be improved after the completion
of this triple flush procedure.
Note: Shudder should improve directionally right away,
but for full affect the vehicle may need to be driven up
to 322 km (200 miles) and at least two cold to hot drive
cycles before determining if the fluid flush corrected the
condition or not. Do not re-evaluate vehicle for
additional customer shudder concerns until the vehicle
has been driven 322 km (200 miles).

Warranty Information
For vehicles repaired under the Bumper-to-Bumper
coverage (Canada Base Warranty coverage), use the
following labor operation. Reference the Applicable
Warranties section of Investigate Vehicle History (IVH)
for coverage information.
Labor
Operation

Description

Labor Time

8480478*

Flush and Drain Fluids for
Transmission Shake and/or
Shutter Repair

Use Actual
Clock Time

*This is a unique Labor Operation for Bulletin use only.

Version

2

Modified

June 01, 2016 - Added breakpoint date.

GM bulletins are intended for use by professional technicians, NOT a "do-it-xourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide mformat1on that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.

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